Re: [PATCH v3 1/2] mm: page_alloc: skip memoryless nodes entirely

Qi Zheng
2023-10-20T09:09:48Z

On 2023/10/20 16:31, Ingo Molnar wrote:
>
> * Qi Zheng <zhengqi.arch@bytedance.com> wrote:
>
>> In find_next_best_node(), We skipped the memoryless nodes
>
> s/We
> /we
>
> s/the memoryless nodes
> /memoryless nodes
>
>> when building the zonelists of other normal nodes (N_NORMAL),
>> but did not skip the memoryless node itself when building
>> the zonelist. This will cause it to be traversed at runtime.
>>
>> For example, say we have node0 and node1, node0 is memoryless
>> node, then the fallback order of node0 and node1 as follows:
>>
>> [ 0.153005] Fallback order for Node 0: 0 1
>> [ 0.153564] Fallback order for Node 1: 1
>>
>> After this patch, we skip memoryless node0 entirely, then
>> the fallback order of node0 and node1 as follows:
>
> s/fallback
> /fall back
>
>>
>> [ 0.155236] Fallback order for Node 0: 1
>> [ 0.155806] Fallback order for Node 1: 1
>>
>> So it becomes completely invisible, which will reduce runtime
>> overhead.
>>
>> And in this way, we will not try to allocate pages from memoryless
>> node0, then the panic mentioned in [1] will also be fixed. Even though
>> this problem has been solved by dropping the NODE_MIN_SIZE constrain
>> in x86 [2], it would be better to fix it in core MM as well.
>
> s/in core MM
> /in the core MM
>
>> [1]. https://lore.kernel.org/all/20230212110305.93670-1-zhengqi.arch@bytedance.com/
>> [2]. https://lore.kernel.org/all/20231017062215.171670-1-rppt@kernel.org/
>>
>> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
>> Acked-by: David Hildenbrand <david@redhat.com>
>
>> + /*
>> + * Use the local node if we haven't already. But for memoryless local
>> + * node, we should skip it and fallback to other nodes.
>
> s/fallback
> /fall back
>
> s/already. But
> /already, but

Will fix the typos above.

>
> Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks.

>
> Thanks,
>
> Ingo